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    The regenerative medicine in oral and maxillofacial surgery: The most important innovations in the clinical application of mesenchymal stem cells

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    Regenerative medicine is an emerging field of biotechnology that combines various aspects of medicine, cell and molecular biology, materials science and bioengineering in order to regenerate, repair or replace tissues.The oral surgery and maxillofacial surgery have a role in the treatment of traumatic or degenerative diseases that lead to a tissue loss: frequently, to rehabilitate these minuses, you should use techniques that have been improved over time. Since 1990, we started with the use of growth factors and platelet concentrates in oral and maxillofacial surgery; in the following period we start to use biomaterials, as well as several type of scaffolds and autologous tissues. The frontier of regenerative medicine nowadays is represented by the mesenchymal stem cells (MSCs): overcoming the ethical problems thanks to the use of mesenchymal stem cells from adult patient, and with the increasingly sophisticated technology to support their manipulation, MSCs are undoubtedly the future of medicine regenerative and they are showing perspectives unimaginable just a few years ago. Most recent studies are aimed to tissues regeneration using MSCs taken from sites that are even more accessible and rich in stem cells: the oral cavity turned out to be an important source of MSCs with the advantage to be easily accessible to the surgeon, thus avoiding to increase the morbidity of the patient.The future is the regeneration of whole organs or biological systems consisting of many different tissues, starting from an initial stem cell line, perhaps using innovative scaffolds together with the nano-engineering of biological tissues

    Human periapical cyst-mesenchymal stem cells differentiate into neuronal cells

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    It was recently reported that human periapical cysts (hPCys), a commonly occurring odontogenic cystic lesion of inflammatory origin, contain mesenchymal stem cells (MSCs) with the capacity for self-renewal and multilineage differentiation. In this study, periapical inflammatory cysts were compared with dental pulp to determine whether this tissue may be an alternative accessible tissue source of MSCs that retain the potential for neurogenic differentiation. Flow cytometry and immunofluorescence analysis indicated that hPCy-MSCs and dental pulp stem cells spontaneously expressed the neuron-specific protein β-III tubulin and the neural stem-/astrocyte-specific protein glial fibrillary acidic protein (GFAP) in their basal state before differentiation occurs. Furthermore, undifferentiated hPCy-MSCs showed a higher expression of transcripts for neuronal markers (β-III tubulin, NF-M, MAP2) and neural-related transcription factors (MSX-1, Foxa2, En-1) as compared with dental pulp stem cells. After exposure to neurogenic differentiation conditions (neural media containing epidermal growth factor [EGF], basic fibroblast growth factor [bFGF], and retinoic acid), the hPCy-MSCs showed enhanced expression of β-III tubulin and GFAP proteins, as well as increased expression of neurofilaments medium, neurofilaments heavy, and neuron-specific enolase at the transcript level. In addition, neurally differentiated hPCy-MSCs showed upregulated expression of the neural transcription factors Pitx3, Foxa2, Nurr1, and the dopamine-related genes tyrosine hydroxylase and dopamine transporter. The present study demonstrated for the first time that hPCy-MSCs have a predisposition toward the neural phenotype that is increased when exposed to neural differentiation cues, based on upregulation of a comprehensive set of proteins and genes that define neuronal cells. In conclusion, these results provide evidence that hPCy-MSCs might be another optimal source of neural/glial cells for cell-based therapies to treat neurologic diseases

    CD146 Expression Influences Periapical Cyst Mesenchymal Stem Cell Properties

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    Recent studies have identified a new human dental derived progenitor cell population with multi-lineage differentiation potential referred to as human periapical cyst mesenchymal stem cells (hPCy-MSCs). In the present study, we compared two subpopulations of hPCy-MSCs characterised by the low or high expression of CD146 to establish whether this expression can regulate their stem cell properties. Using flow cytometry, we evaluated the stem cell marker profile of hPCy-MSCs during passaging. Furthermore, CD146Low and CD146High cells were sorted by magnetic beads and subsequently both cell populations were evaluated for differences in their proliferation, self-renewal, stem cell surface markers, stemness genes expression and osteogenic differentiation potential. We found that hPCy-MSCs possessed a stable expression of several mesenchymal stem cell surface markers, whereas CD146 expression declined during passaging. In addition, sorted CD146Low cells proliferated significantly faster, displayed higher colony-forming unit-fibroblast capacity and showed higher expression of Klf4 when compared to the CD146High subset. Significantly, the osteogenic potential of hPCy-MSCs was greater in the CD146Low than in CD146High population. These results demonstrate that CD146 is spontaneously downregulated with passaging at both mRNA and protein levels and that the high expression of CD146 reduces the proliferative, self-renewal and osteogenic differentiation potential of hPCy-MSCs. In conclusion, our study demonstrates that changes in the expression of CD146 can influence the stem cell properties of hPCy-MSCs

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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